Mitral valve repair is the procedure of choice to correct mitral regurgitation of all etiologies. With the use of current surgical techniques, between approximately 70% and 95% of regurgitant mitral valves can be repaired. The advantages of mitral valve repair over mitral valve replacement are well-documented. These include better preservation of cardiac function and reduced risk of anticoagulant-related hemorrhage, thromboembolism and endocarditis.
Nearly all mitral valve repairs include an annuloplasty. The annuloplasty consists of a suture or prosthetic ring that surrounds all or part of the circumference of the annulus of the mitral valve. The annuloplasty serves several functions: it remodels the annulus of the valve; it decreases tension on suture lines; it increases leaflet coaptation; and it prevents recurrent annular dilatation. In addition, the annuloplasty improves repair durability.
Most current annuloplasty techniques require the placement of sutures in the mitral annulus followed by placement of a prosthetic band or ring. This technique can be time-consuming and technically difficult. Furthermore, using current techniques, the annuloplasty requires cardiopulmonary bypass, cardiac arrest, and a large incision in the chest wall and heart.
It is well-known that cardiopulmonary bypass is associated with significant morbidity and mortality. Recognition of the damaging effects of cardiopulmonary bypass has been the impetus for significant advances in beating heart coronary artery bypass grafting. As a consequence, approximately 20% to 35% of all coronary artery bypass grafting is now performed on a beating heart. To date, however, there are no clinically-applicable techniques for performing mitral valve surgery on a beating heart without the use of a heart-lung machine. Therefore, mitral valve repair by annuloplasty currently entails a major operation that includes all of the complications attributable to cardiopulmonary bypass.
In current practice, all patients judged to be candidates for mitral valve surgery must face the risk of cardiopulmonary bypass and cardiac arrest. Therefore, patients early in their disease process (i.e., those who have not yet suffered significant cardiac damage) generally have surgery deferred until they develop troubling symptoms or cardiac dysfunction. Conversely, other patients (i.e., those with poor cardiac function and other co-morbidities) are frequently denied surgery as the risk associated with cardiopulmonary bypass and cardiac arrest is too high.
Mitral regurgitation is common in patients with poor cardiac function and heart failure. It is well known that mitral regurgitation contributes significantly to the debilitating symptoms of such patients. Correction of mitral regurgitation would improve symptoms and, possibly, longevity in such patients. Furthermore, it is believed that mitral regurgitation contributes to the deterioration of left ventricular function. Thus, correcting mitral regurgitation may halt further decline in ventricular function and may, in fact, cause improvement in ventricular function.
Unfortunately, however, such heart failure patients are at high risk for mitral valve surgery using current techniques. By way of example, the operative mortality for mitral valve surgery in patients with left ventricular dysfunction is approximately 5% to 15%. Therefore, the majority of such patients are not deemed candidates for mitral valve repair using currently available techniques.
Development of a system and method for mitral valve annuloplasty that does not require cardiopulmonary bypass would extend the benefits of mitral valve repair to a large segment of the heart failure population.
Accordingly, one object of the present invention is to provide an improved system for the repair of heart valves.
Another object of the present invention is to provide an improved system for the repair of heart valves so as to improve their efficiency.
And another object of the present invention is to provide an improved system for the repair of mitral valves.
Still another object of the present invention is to provide an improved system to reduce mitral regurgitation.
Yet another object of the present invention is to provide an improved system for mitral valve annulopasty.
Another object of the present invention is to provide an improved system for the repair of mitral valves that can be used with other repair techniques that might involve leaflets, chordae tendina and/or papillary muscles.
Another object of the present invention is to provide a novel system that may stabilize or improve left ventricular function.
Another object of the present invention is to provide a novel system that may treat congestive heart failure.
Another object of the present invention is to provide a novel system that may prevent the development of mitral regurgitation, prospectively.
And another object of the present invention is to provide a novel system for the repair of mitral valves that eliminates the need for cardiopulmonary bypass and/or cardiac arrest.
Still another object of the present invention is to provide a novel system for the repair of mitral valves that facilitates the use of smaller incisions.
Yet another object of the present invention is to provide a novel system for the repair of mitral valves that affords a percutaneous approach to the mitral valve.
Another object of the present invention is to provide a novel system for the repair of mitral valves, wherein the system can be employed to perform mitral valve repair via a partial or complete annuloplasty, either on an arrested heart or on a beating heart, with or without the use of cardiopulmonary bypass, or on a fibrillating heart.
Another object of the present invention is to provide an improved method for the repair of heart valves.
Another object of the present invention is to provide an improved method for the repair of heart valves so as to improve their efficiency.
And another object of the present invention is to provide an improved method for the repair of mitral valves.
Still another object of the present invention is to provide an improved method to reduce mitral regurgitation.
Yet another object of the present invention is to provide an improved method for mitral valve annulopasty.
Another object of the present invention is to provide an improved method for the repair of mitral valves that can be used with other repair techniques that might involve leaflets, chordae tendina and/or papillary muscles.
Another objective of the present invention is to provide a novel method that may stabilize or improve left ventricular function.
Another object of the present invention is to provide a novel method that may treat congestive heart failure.
Another object of the present invention is to provide a method that may prevent the development of mitral regurgitation, prospectively.
And another object of the present invention is to provide a novel method for the repair of mitral valves that eliminates the need for cardiopulmonary bypass and/or cardiac arrest.
Still another object of the present invention is to provide a novel method for the repair of mitral valves that facilitates the use of smaller incisions.
Yet another object of the present invention is to provide a novel method for the repair of mitral valves that affords a percutaneous approach to the mitral valve.
Another object of the present invention is to provide a novel method for the repair of mitral valves, wherein the method can be employed to perform mitral valve repair via a partial or complete annuloplasty, either on an arrested heart or on a beating heart, with or without the use of cardiopulmonary bypass, or on a fibrillating heart.
These and other objects of the present invention are addressed by the provision and use of a novel system and method for performing partial or complete mitral valve annuloplasty using a novel device that creates a measured plication of the mitral annulus. The device can be inserted into the left atrium via (1) a partial or complete sternotomy; (2) a right or left thoracotomy, with or without a thorocoscope; or (3) a central or peripheral vein via the right atrium and interatrial septum.
Alternatively, the device may be applied to the outside of the heart, via any incision, such that the device effects a geometrical change in the annulus. Alternatively, the device can be inserted into any cardiac vein or artery in the heart such that the device causes a geometric change in the mitral annulus.
Further, the device may be applied to the outside of the heart in association with another device such as a restraining device used for the treatment of heart failure. In so doing, the device may be responsible for altering the mitral valve and/or left ventricle in such a way as to influence mitral regurgitation, heart function, and/or congestive heart failure.
Visualization of the device within the left atrium can be facilitated by transesophageal echocardiography; epicardial echocardiography; fluoroscopy; angioscopy; an ultrasound probe that is or is not an integral part of the device; or an angioscope that is or is not an integral part of the device.
The device is adapted to deploy plication bands into the mitral annulus. Each plication band comprises two ends which penetrate the tissue of the mitral annulus, thereby affixing the plication band to the annular tissue. Preferably each plication band engages about 5-15 mm of annular tissue. As the plication band is deployed, it plicates the annular tissue immediately below the plication band by about 30% to 50%, thereby reducing the annular circumference of the mitral annulus in measured increments. The distal end of the device, which has a range of motion controlled by the operator, may then be rotated 180 degrees, thus maintaining a point of engagement with the mitral annulus (or, if desired, the left atrium). Alternatively, the device may be detached completely from the annulus before deployment of the next plication band. The aforementioned rotation of the device can be helpful since it can aid in the measured placement of the next plication band. However, there may be occasions in which the operator may not want the device to rotate. In that situation, the same or similar device may be used without rotation.
The plication bands may be separate from one another, or they may be attached to one another via a linkage construct. Where a plurality of plication bands are attached to one another via a linkage construct, the valve annulus may also be reduced by a shortening of the length of the linkage construct between each plication band so as to gather together the tissue between each plication band.
Each plication band may be constructed of a substantially rigid or semi-flexible metal or other material. The plication band is adapted to be non-thrombogenic and may be coated, in whole or in part, by a material designed to promote tissue in-growth and reduce thromboembolism. By way of example but not limitation, such material might be dacron, polyester velour, pericardium, or some other suitable material.
The device may be used on a fully arrested heart with the patient on cardiopulmonary bypass, or on a beating heart with or without cardiopulmonary bypass, or on a fibrillating heart. If employed on a beating heart or on a fibrillating heart, the device may be introduced into the left atrium via the left atrium wall, a pulmonary vein, the left atrial appendage, or percutaneously into the left atrium via a systemic vein. The device may also be introduced into the left atrium via the arterial system and across the aortic valve. If employed during cardiopulmonary bypass, the device may be introduced into the left atrium in a similar fashion, with or without robotic assistance.
It should be appreciated that while the device is generally discussed herein with reference to its use in mitral valve repair, it is also contemplated that the same or substantially similar device and methodology may be used in the repair of other cardiac valves, including the tricuspid valve, the pulmonary valve, and the aortic valve.